English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The X-ray afterglow of GRB 130831A shows an "internal plateau" with a decayslope of $\sim$ 0.8, followed by a steep drop at around $10^5$ s with a slopeof $\sim$ 6. After the drop, the X-ray afterglow continues with a muchshallower decay. The optical afterglow exhibits two segments of plateausseparated by a luminous optical flare, followed by a normal decay with a slopebasically consistent with that of the late-time X-ray afterglow. The decay ofthe internal X-ray plateau is much steeper than what we expect in the simplestmagnetar model. We propose a scenario in which the magnetar undergoesgravitational-wave-driven r-mode instability, and the spin-down is dominated bygravitational wave losses up to the end of the steep plateau, so that such arelatively steep plateau can be interpreted as the internal emission of themagnetar wind and the sharp drop can be produced when the magnetar collapsesinto a black hole. This scenario also predicts an initial X-ray plateau lastingfor hundreds of seconds with an approximately constant flux which is compatiblewith observation. Assuming that the magnetar wind has a negligible contributionin the optical band, we interpret the optical afterglow as the forward shockemission by invoking the energy injection from a continuously refreshed shockfollowing the prompt emission phase. It is shown that our model can basicallydescribe the temporal evolution of the multi-band afterglow of GRB 130831A.

Modeling the Multi-Band Afterglow of GRB 130831A: Evidence for a Spinning-Down Magnetar Dominated by Gravitational Wave Losses?